Massive pulmonary embolism in a pregnancy: could we have saved both lives? Ida Lilywaty Latar a , Siti Zawiah Omar a , Chan Yoo Kuen b , Vallikkannu Narayanan a a Department of Obstetrics & Gynaecology, Faculty of Medicine, University of Malaya, 50603 K.Lumpur, Malaysia
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Massive pulmonary embolism in a pregnancy: could we have saved both lives?
Ida Lilywaty Latar a, Siti Zawiah Omar a, Chan Yoo Kuen b , Vallikkannu Narayanana
a Department of Obstetrics & Gynaecology, Faculty of Medicine, University of Malaya, 50603 K.Lumpur, Malaysia
b Department of Anaesthesiology, Faculty of Medicine, University of Malaya, 50603 K.Lumpur, Malaysia
A 19-year old, non-diabetic primigravida at 32 weeks gestation presented with right thigh abscess. Blood investigations were normal except that platelet was low (128 x 109/L ). An ultrasound examination upon admission revealed a normal, singleton pregnancy. Saucerisation of the abscess was performed under general anaesthesia (GA). She was nursed in the orthopaedic ward and was put on intravenous antibiotics with regular wound dressing.
She underwent another 2 procedures of saucerisation due to poor wound healing within the subsequent 5 days. Following the third procedure, noted both lower limbs were swollen with the involved one more oedematous than the other. In view of high possibility of deep vein thrombosis (DVT) she was started on therapeutic dose of low molecular weight heparin (LMWH). A compression ultrasound revealed bilateral DVT at the level of common femoral vein.
Seven hours later she developed sudden onset of chest pain and shortness of breath. Blood pressure was 132/70mmHg, pulse rate of 120-130/min. She deteriorated within seconds with oxygen saturation dropped from 97% to 75%. Arterial blood gas showed metabolic acidosis with pH of 7.30 and base excess of -19.0. Haemoglobin was 8.6g/dL with platelet of 34 x 109/L . White blood cell count of 31.0 x 109/L with predominant neutrophils. She was immediately intubated with the impression of acute pulmonary embolism (PE) with underlying sepsis. A CT pulmonary artery (CTPA) done confirmed a large saddle embolus over main pulmonary trunk with right base of lung infarct (Figure 1).
Echocardiogram revealed a dilated right atrium and ventricle with underfilling of left ventricle. A multidisciplinary team decision was made to insert a retrievable inferior vena cava (IVC) filters followed by pulmonary embolectomy and bypass surgery. In view of extremely low platelet with full heparinization, it was considered hazardous to have caesarean section preceding the bypass surgery.
During the IVC filter insertion, we noted that the output of the right heart worsened with extreme widening of the alveolar-arterial carbon dioxide concentration . It was at this junction that the fetal heart sound was noted to beno longer detectable. We proceeded with pulmonary embolectomy with cardiopulmonary bypass (Figure 2). Nine hours later, she went into spontaneous labour and delivered a 1700g fresh stillbirth uneventfully. She was restarted on LMWH and extubated two days later.
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Pulmonary embolectomy is an option in life threatening PE as in the case of this patient. Pulmonary embolectomy carries the highest maternal mortality of approximately 22% and fetal-neonatal mortality of 30% .An open cardiac surgery in the third trimester might be best managed by a caesarean section followed immediately by a cardiac operation. A caesarean section can be undertaken safely before cardiopulmonary bypass without inducing uterine haemorrhage .
Preoperative insertion of an IVC filter is useful to prevent intraoperative PE in a patient with a history of DVT. However, the safety of IVC filter use in pregnancy is uncertain, as data are limited. A few case series did not identify any problems associated with IVC filter placement or continuation in pregnancy .
In this emergent case, LMWH was started prior to the decision of embolectomy with caution in view of severe thrombocytopaenia. Due to the fear of haemorrhage, UFH and thrombolytic agents were deemed to be not suitable.
The possible risks of severe thrombocytopaenia due to sepsis following large thigh abscess may contribute to haemorrhage during caesarean section. This gives an added risk of requiring hysterectomy at her young age with major impact on her future fertility. These have deterred the decision to perform caesarean section prior to embolectomy. Indication for IVC filter placement and embolectomy was based on her critically ill condition with high risk for recurrent embolism as another embolism will likely be fatal for her.
Intrauterine death diagnosed following insertion of IVC filter may be possibly due to occurence of further emboli during the procedure that increases burden to pulmonary circulation and cardiac output leading to placental hypoperfusion. Additionally, the set up during the procedure of IVC filter insertion did not permit the parturient to be properly placed in the left lateral position. This may have further compromised venous return, cardiac output and blood flow to the fetus which may result in its demise.
Figure 1: CTPA features of saddle embolus over main pulmonary trunk
Figure 2: Blood clots removed from embolectomy over main pulmonary trunk
This was a life threatening situation where a young primigravida presented with severe sepsis with thrombocytopaenia, bilateral pulmonary embolism (PE) while being fully anticoagulated.
The effect of large thrombus burden in the pulmonary circulation mainly due to acute reduction in cardiac output can result in critical organ malperfusion, multiorgan failure and possible death. Another effect is caused by acute or long term obstruction to the pulmonary circulation which can facilitate pulmonary hypertension.
In the acute phase of pulmonary embolism (first 24 hours), 10% of non-pregnant patients with PE die before diagnosis . Low molecular weight heparin (LMWH) is the treatment of choice for PE in pregnant patients. Unfractionated heparin (UFH) is only used when LMWH is unavailable. Both drugs potentiate antithrombin’s anti-activated coagulation factor activity and further restrict thrombus formation which further allows time for fibrinolysis of the established thrombus. The advantaged of LMWH compared with UFH include longer half-life and better bioavailability with lower risk of heparin induced thrombocytopaenia .
Increasing evidence and published data now supports the use of thrombolysis in pregnancy for the treatment of massive PE in this life threatening situation. Few report the successful treatment of massive PE with thrombolytic agents without any severe adverse events . Thrombolytic drugs can be considered for the treatment of patients who are haemodynamically unstable, patients with refractory hypoxaemia or right ventricular dysfunction on echocardiogram .However, the maternal mortality rate from thrombolytic therapy has been reported to be 1.2%, the bleeding rate 8.1%, and the fetal loss rate 5.8% .